ABSTRACT
This chapter reviews habitat impacts of seawalls and how these impacts can be mitigated and present a case study of Seattle's seawall habitat improvements. It indicates that benches, beaches, and "bumps" added to Seattle's seawall can have beneficial effects. The ecology of intertidal areas is driven by the physical environment, which is modified by shoreline armoring. Important differences between seawalls and natural rocky intertidal shorelines include habitat heterogeneity and complexity that tend to be lacking on seawalls. When the Seattle Art Museum's Olympic Sculpture Park opened in 2007, it included two major enhancements intended to benefit juvenile salmon: a ~290-m-long habitat bench projecting from the base of the seawall with sediment simulating more natural conditions than those found along most of Seattle's waterfront and a ~100-m-long pocket beach excavated from a stretch of riprap-armored shoreline and surfaced with pebbles and cobbles. Habitat improvements along extremely urbanized shorelines are obviously constrained by human uses and the infrastructure needs of a city.
